Method for controlling a power flow

ABSTRACT

A method for controlling power sources or energy sinks on an energy accumulator, in particular for a motor vehicle, is disclosed. Conventional systems for power supply to the motor vehicle modules are often excessively used, in particular in utility vehicles when an optimal availability is required. The present method includes measuring parameters characterizing the charge of the accumulator, and transmitting the results of a measurement to a control unit and in generating control signals for the energy sinks or the power sources by a control unit. The method makes it possible to eliminate a frequent cause of a low availability in motor vehicles.

The invention relates to a method for controlling energy sources orenergy sinks on an energy accumulator, in particular in a motor vehicle.

The subject matter of the invention relates mainly to the field ofautomobile engineering in which case, in consequence, the expressionsenergy accumulator and battery or vehicle battery are used synonymously.

Electrical couplings or clutches, electrically operated lifting ramps,winch motors, drive-by-wire controllers, steer-by-wire controllers,electrical retarder supports, automotive image identification systems,radar-sensor systems, information system modules for organization of theunloading and loading of commercial vehicle cargoes on fleet parkingareas and various further electrically operated systems assist thedriver to carry out his tasks. The large number of these electronicinformation, control and loading systems, the increasing electrificationof previously mechanical driving aids and equipment, and the increasinglevel of motorization with correspondingly larger starting aids requirea large amount of electrical energy, and thus have a direct influence onthe life of vehicle batteries. In consequence, any shortage in thebattery-fed energy supply in vehicles such as these also results in adrastic increase in the risk of breakdown. Vehicles with a high risk ofbreakdown, in particular commercial vehicles, do not comply with therequirements for a high degree of mobility, and can be used only to arestricted extent.

Various apparatuses and methods for optimization of the state of chargeand thus also of the life of vehicle batteries are already known, andare currently used in particular cases in passenger vehicles. By way ofexample, batteries are equipped with sensors and actuators whichreadjust their own temperature when cold. In consequence, the chemicalreaction rates are increased, and the battery can be recharged within ashorter time. So-called integrated battery diagnosis systems are alsoknown, which are integrated directly in the battery as a smallelectronic assembly, and lengthen the life of the battery.

However, none of the abovementioned systems overcomes the reason forrestrictions to the availability of energy accumulators and the highcosts associated with them as a result of their failures.

In this context, the invention is based on the object of specifying amethod of the type mentioned initially, which ensures that an energyaccumulator, in particular a vehicle battery, is operated in as optimuma fail-safe manner as possible. An apparatus for carrying out the methodis also the subject matter of the invention.

According to the invention, the object is achieved by means of thesubject matter of the first claim and of claim 9. The respectivedependent claims describe advantageous refinements and developments ofthe solution found.

The state of charge of the battery depends not only on the batterycharacteristic data but also on a large number of further factors. Inaddition to the battery characteristic variables, the acid levels of thebattery, the load power levels, the charging voltage, the dynamic systemcharacteristics and the nature of the vehicle use also govern the lifeof the battery, and hence also the risk of the vehicle breaking down.

The central element that is currently implemented in all vehicles fordetection of a large number of parameters which are relevant for thestate of charge of the battery, such as the vehicle power supply systemvoltage, the rotation speed, the speed, the temperatures, etc., and forcontrolling a large number of electrical loads, is the instrumentationunit, in this case referred to for short as the combination instrument.The information flow which coincides here, combined with the capabilityto control parameters relating to the system-internal power flows, isparticularly suitable for integration of the method described in thisinvention. The present trend for modularization of individual systemcomponents in the vehicle and for connection to universal networks, suchas CAN, RS485, LON or K-line, is opening up the option not only offurther concentration of functionality in the combination instrument,but also of centrally influencing virtually all system components andloads in the vehicle. In addition, connections which are notcable-based, such as Bluetooth, also according to the invention allowthe control of components which are not wired in as standard, forexample retrofitted components. The central implementation offunctionalities in a control unit makes it possible to avoid some of thesensitive electronics, thus improving the reliability and lengtheningthe life of the overall system.

A further advantage of the invention is the use of criteria which allowadaptation of the method and of its implemented routines to differentenergy sinks and energy sources, such as different battery types, thusmaking it possible to ensure use that is as versatile as possible. Inaddition to automatic control by the system, active, assessing, manualaction on the overall system is also possible, thus allowing adaptationsto be carried out for different situations and characteristics relevantto the vehicle and the journey profile.

One advantageous development of the invention advantageously usesapparatuses and methods for evaluation and control of driver-relevant,transport-logistic or vehicle-relevant data, with the apparatuses ormethods that can be used being, for example, so-called generatorregulators, electronic battery heating management systems, temperaturesensors for the battery and the engine bay, acid density meters forbatteries, sensors and actuators for energy sources and energy sinks,route planners, detectors for detection of system characteristics,systems for controlling ignition and injection systems (engine control),and systems for controlling logistic processes for passenger vehicle andcommercial vehicle traffic.

In order to provide further illustration, the most important of theapparatuses and methods mentioned above will be explained or definedbriefly in the following text.

Generator regulators compensate for the voltage differences caused byrotation speed and load fluctuations.

Battery heating management systems use a measurement and control unitwhich is located in the battery housing to determine the temperature ofthe battery, and to readjust it.

Acid density meters for batteries determine the acid density and acidstratification of the batteries.

Acid regulators compensate for chemically non-uniform states.

Load meters and load controllers for loads in the vehicle determine andcontrol the energy and time profile of continuous loads, long-term loadsand short-term loads.

Detectors on the battery detect the interaction of battery, generator,loads, temperature, rotation speed and transmission ratio from theengine to the generator, and transmit a characteristic which describesthis system.

Systems for controlling the ignition and injection system or enginemanagement systems, such as motronic systems, detect and controlinstantaneous engine operating data and communicate with other vehiclecontrollers.

Systems for controlling individual goods vehicles and goods vehiclefleets, so-called wap-log systems, analyze the processes relating totransport logistics. The company procedures with generally differenttypes of traffic are stored in a database. Depending on the specificapplication, a relevant model is activated, in which details of the taskprocesses and of the present order are recorded, so that the driver isguided through his journey profile by mobile radio step-by-step by meansof an information system which is based on a wireless applicationprotocol, referred to for short as WAP, on the general packet radioservice, referred to as GPRS for short.

The battery temperature at which the engine can still be started dependson the minimum state of charge of the battery.

The current emitted from the generator is dependent on the rotationspeed. If the load current is greater than the generator current, forexample when the engine is idling, the battery is discharged, and thevoltage in the vehicle power supply system falls.

The rotation speed which is offered to the generator depends on the useof the vehicle, such as commercial traffic, driving on freeways, drivingin towns, etc.

The load power levels are governed by the electrical loads. In avehicle, these comprise permanent loads (ignition, fuel injection,etc.), long-term loads (lighting, brake light, etc.) and short-termloads (blinkers, brake light, etc.), and they are switched on fordifferent periods. In some cases, they are dependent on the time of year(air-conditioning system, seat heating) or are dependent on the type ofdriving (cooling fans).

The charging voltage has to vary depending on the chemical processes inthe battery. Cold requires a high charging voltage, while heat requiresa lower charging voltage.

The interaction of the battery, generator, loads, temperature, rotationspeed and transmission ratio from the engine to the generator isdescribed by the system characteristic. This changes dynamicallydepending on the vehicle operating condition.

The battery acid levels determine the density of the electrolyte, whichis provided as the ion conductor between the pole plates, varying withthe charging voltage, and can be used as a measure for this. Typicalvalues between a charged battery and a discharged battery fluctuate inthe case of low-acid rechargeable batteries (PbO2-H2So4-Pb) between 1.28kg/l and 1.04 kg/l.

The maximum power of the generator rises with the rotation speed. In thecase of modern vehicles, engine idling represents about one-third of therotation speed probabilities of the generator. The power emitted fromthe generator is controlled by means of the field current. The currentoutput function has a curved profile when plotted against the rotationspeed. This so-called maximum current characteristic rises from the0-ampere rotation speed up to the idling rotation speed, but then risesonly slightly up to the maximum rotation speed, in order to ensureoverload protection.

The systems are controlled by means of a generator regulator,specifically a standard regulator or multifunction regulator. Standardregulators normally have a temperature-dependent preset nominal value,which is higher when it is cold in order to improve battery recharging,which is then more difficult. Modern multifunction regulators have aninterface which, within certain limits, allows fine tuning with respectto the engine operating state.

Engine management systems are systems for controlling the ignition andinjection system, such as motronic systems, and carry out the detectionand control of instantaneous engine operating data, on amicroprocessor-controlled basis. They communicate with other vehiclecontrollers via the CAN bus system. Typical engine operating dataincludes the accelerator pedal position, the ignition data, the airflows, the rotation speed, the temperatures, the battery voltage, thefuel flow, the speed of travel, the torque, the mixture ratio, theexhaust gas data, etc.

The method according to the invention can advantageously provide forprioritization, filtering and normalization of various data formats tobe carried out with the aid of a data mask. This means that the actualcore algorithm for generation of control signals for power loads orpower feeders remains free of module-specific data format corrections,and is thus clear.

One embodiment of the method according to the invention is particularlyexpedient when the future time profile of the state of charge of theenergy accumulator is signaled to a user, in particular being indicatedon a display or signaled acoustically. The vehicle driver of the motorvehicle therefore does not have to blindly trust a system with themethod according to the invention and can always reassure himself thatthe procedure proposed by the method is worthwhile.

The control unit which generates control signals can expediently beconnected to actuators by means of which engine parameters can beadapted. By way of example, a controller for an automatic transmissioncan be matched with respect to the rotation speed behavior on load insuch a way that the drive rotation speed for the generator is increasedwhen required. In addition, however, it is also expedient to connectactuators to the control unit which control high-load infotainmentelements on a state of charge-dependent basis, for example switchingthem off when the state of charge is critical. The method according tothe invention is additionally optimized if the control unit is able tocalculate the energy consumption of energy sinks on the planned route inadvance, for example by using data from a navigation system andvehicle-specific characteristic data to produce an appropriateprediction.

It is particularly expedient for the control unit according to theinvention to be integrated as a component in a combination instrument.Combination instruments are already a destination point for all theinformation flows from the motor vehicle system.

One preferred variant of the solution found provides for logic linkingand assessment of some of the data obtained by means of theabovementioned apparatuses and methods to be carried out in thecombination instrument such that either optionally or automatically on apredetermined basis an energy situation is recommended which has beenoptimized for the overall system comprising the vehicle, the roadway andthe route, or a situation is forced that offers an optimized chargingstate and final charge state for the energy accumulator or the battery.

The method is advantageously implemented by means of an apparatusaccording to the invention, which expediently has a control unit that isincluded in a combination instrument, with the control unit having aremote data transmission module, an engine management module, a batterymanagement module, a temperature module, a data input module, a filter,a memory, a logic module, a wire-free load controller or a wire-basedload controller.

The invention will be explained in more detail in the following text onthe basis of one specific exemplary embodiment and with reference to adrawing for illustrative purposes, without any restriction to thisexample. In the figure:

FIG. 1: shows a system sketch of an apparatus which operates using themethod according to the invention.

FIG. 1 illustrates the data flows of input and output parameters 1 to 8,with the input and output parameters 1 to 6 being explained in detail inthe following text, and the input and output parameters 7 to 8 beingdescribed as being representative of further channels which may possiblynot always be used.

Essentially, a control unit 10 according to the invention forcontrolling energy sources 21 or energy sinks 22 on an energyaccumulator 23 comprises input and output modules 1 to 8, a filter 9 formatching, standardization and normalization of data formats from or forthe input and output modules 1 to 8, a logic module 12, a memory 11, awire-free load controller 13 and a wire-based load controller 14. All ofthe abovementioned modules 1 to 14 have a connection which can carry abidirectional data flow to the connected adjacent module, with the inputand output modules 1 to 8 each being connected to the filter 9, with thefilter 9 being connected to the memory 11 and to the logic module 12,and with the logic module 12 having a corresponding link to the loadcontrollers 13, 14. The bidirectional data flow is illustrated in FIG. 1by means of a double-headed arrow which has a centrally arranged circlesymbol. A unidirectional call to a module by means of a module connectedadjacent to it is in each case symbolized by a single arrow, as well.The input and output modules 1 to 8 call the filter 9, via a bus that isnot illustrated, when data or measurement data is present. The filter 9starts a call or is called by the modules, the logic module 12 and thememory 11. The logic module 12 calls the load controllers 13 or 14 asrequired.

The energy accumulator 1 is in the form of a passive energy source,specifically a battery. The data to be transmitted to the filter 9 isinformation from a battery management system, temperatures of thebattery and chemical data.

The energy source 2 or the generator 21 which is illustrated in FIG. 1,once again for simplicity purposes, in the connection of the generator21, energy accumulator 23 and load 22, comprises all of the activeenergy sources, specifically generators, generator regulators, solarcollectors or external electrical power supplies connected to thevehicle.

Data is transmitted from a remote data transmitter 3 to the filter 9 andis used in the method for determination and for adjustment of a drivingsituation or route which is advantageous for charging and discharging ofthe battery. The state of charge and the charging time predictions aretransmitted to a wap-log system, which transmits an optimized route backto the system according to the invention, on the basis of this data.

An engine management module 4 transmits parameters relating to theignition system and to the injection system to the filter 9, inparticular engine temperatures and the rotation speed. The system usesthis data to identify whether the driver or the vehicle controllershould initiate a higher rotation speed in order that the generator 21will produce a higher charging current.

A battery management module 5 supplies the filter 9 with informationrelating to the electronic battery management, in particular heatmanagement. This essentially comprises the temperature data for theenergy accumulator 1, with an operating temperature that is advantageousfor the energy accumulator 1 being produced.

A temperature module 6 supplies the control unit 10 according to theinvention, via the filter 9, with data relating to the temperatures inthe engine bay, temperatures relating to the engine, and externalambient temperatures.

The filter 9 comprises a data mask which prioritizes the data from themodules 1 to 8, adapting and filtering it with respect to the dataformat. In addition, information is assessed and weighted in advance inthe filter 9 relating to its importance for the driver, for the roadway,for the vehicle, for the energy sources and for the energy sinks, inorder to achieve a processing time in the logic module 12 that is asshort as possible.

Data to be buffer-stored is stored temporarily or permanently in amemory 11, so that it is available at short notice to the program whenrequired.

The information relating to the data mask, with prioritization andfiltering 9, and the data from the memory 11 are logically linked andcalculated in the logic module 12, so that the results can then beprocessed further and preprocessed in the module for prioritization andfiltering 9.

In the further method procedure, the individual control and measurementunits described above, such as a generator regulator, electronic batteryheat management systems, temperature sensors for the battery and theengine bay, acid density meters for batteries, sensors and actuators forenergy sources and energy sinks, route planners, detectors for detectionof system characteristics, systems for controlling the ignition andinjection system, and systems for controlling logistic procedures inpassenger vehicle and commercial vehicle traffic are instructed via theinput and output modules 1 to 6, so that they can then be subjected bymeans of automatic control or by the driver to manipulation, such asactivation, reduction of the rotation speed, connection of a secondstarter battery, indication of a good route from the energy point ofview, heating of the battery, connection or disconnection of furtherenergy sources, dimming of the lighting, load-related control ofintelligent headlights, partial disconnection of individual infotainmentelements, etc. The module 13 is used to control energy sinks 22 orloads, which are not specified in any more detail, via a wire-freeconnection, by means of simple status information from the load andsimple directives relating to the permissible energy consumption, thatis optimum from the energy point of view.

The module 14 controls energy sinks 22 or loads, which are not specifiedin any more detail, using wires, by the provision of digital on/offcontrol signals.

The exemplary embodiment envisages manipulation of the load-relatedcontrol of various energy sinks 22 or loads, as will be explained inmore detail in the following text for “intelligent headlights”.“Intelligent” headlights, which use the advanced front-lighting system(which is currently in experimental use), are also able to supply powerto the lamps, by means of a controller. This headlight is connected tothe vehicle CAN bus. The intensity and direction of the beam from thefront head-light can be controlled specifically by the use of lenses,mirrors or a DMD (digital micromirror device). The power and beamcontrol are controlled in such a way as to achieve an optimum state ofcharge. In order to avoid adverse effects on driving safety resultingfrom lack of lighting of the roadway, necessary restrictions can beimplemented, for example by reducing the maximum speed, by actions onthe engine controller.

1.-19. (canceled)
 20. A method for controlling energy sources or energysinks on an energy accumulator, in particular in a motor vehicle, themethod comprising the steps of: measuring at least one parameter whichcharacterizes the state of charge of the energy accumulator,transmitting the parameter which characterizes the state of charge ofthe energy accumulator to a control unit, generating by the control unitat least one control signal as a function of the parameter which ischaracteristic of the state of charge of the energy accumulator, whichcontrol signal controls energy sinks or energy sources which areconnected directly or indirectly to the energy accumulator, in terms ofthe power which they consume from the energy accumulator or the powerwhich they emit to the energy accumulator, and calculating by thecontrol unit the energy consumption of energy sinks on a planned routein advance.
 21. The method according to claim 20, wherein the controlunit generates the control signal in a manner to control the energysources or energy sinks, in that the energy accumulator has a positiveenergy balance in a defined time unit, or a positive power balance. 22.The method according to claim 20, wherein the controller calls upmeasurements and/or characteristic variables of the electricalcharacteristics of the energy accumulator (1) and/or generator currentsand/or acid levels of the energy accumulator and/or the engine rotationspeed and/or the engine temperature and/or the energy accumulatortemperature and/or the ambient temperature and/or the dynamic systemcharacteristic, in particular of the energy accumulator, and/or ignitiondata for engine ignition and/or injection system data and/or datarelating to the motronic system, and/or data from systems which arerelated to the motronic system, and/or engine operating data, and/ordata relating to continuous loads and/or data from long-term loads,and/or data from short-term loads, and/or data from charging voltagesand/or GPS data, and/or data from route planners, and/or data fromwap-log systems, and/or data from systems which are related to wap-logsystems, and generates the control signal completely or partially as afunction of this data.
 23. The method according to claim 20, wherein adata mask carries out prioritization, filtering and normalization ofdifferent data formats.
 24. The method according to claim 20, wherein afuture time profile of the state of charge of the energy accumulator issignaled to a user, in particular being indicated on a display orsignaled acoustically.
 25. The method according to claim 20, wherein thecontrol unit is connected to actuators by means of which engineparameters can be adapted.
 26. The method according to claim 20, whereinthe control unit is connected to actuators, by means of which the powerconsumption of infotainment elements or of internal or external vehicleillumination can be controlled.
 27. An apparatus for controlling energysources and energy sinks comprising: means for measuring at least oneparameter which characterizes the state of charge of the energyaccumulator, means for transmitting the parameter which characterizesthe state of charge of the energy accumulator to a control unit, meansfor generating by the control unit at least one control signal as afunction of the parameter which is characteristic of the state of chargeof the energy accumulator, which control signal controls energy sinks orenergy sources which are connected directly or indirectly to the energyaccumulator, in terms of the power which they consume from the energyaccumulator or the power which they emit to the energy accumulator, andmeans for calculating by the control unit the energy consumption ofenergy sinks on a planned route in advance, wherein the control unit isa component of a combination instrument which also comprises a majorpart of the vehicle instrumentation and the control unit is designed insuch a way that it calculates the energy consumption of energy sinks ona planned route in advance.
 28. The apparatus according to claim 27,wherein the control unit has a remote data transmission module.
 29. Theapparatus according to claim 27, wherein the control unit has an enginemanagement module.
 30. The apparatus according to claim 27, wherein thecontrol unit has a battery management module.
 31. The apparatusaccording to claim 27, wherein the control unit has a temperaturemodule.
 32. The apparatus according to claim 27, wherein the controlunit has a data input module.
 33. The apparatus according to claim 27,wherein the control unit has a filter.
 34. The apparatus according toclaim 27, wherein the control unit has a memory.
 35. The apparatusaccording to claim 27, wherein the control unit has a logic module. 36.The apparatus according to claim 27, wherein the control unit has awire-free load controller.
 37. The apparatus according to claim 27,wherein the control unit has a wire-based load controller.